Fit the replacement MPU LED the right way round

When replacing LED CR8 in the reset area, match the flat side of the new LED to the position of where the old LED's flat side was.

Systems

• Bally MPU AS-2518-17
• Bally MPU AS-2518-35
• Stern MPU-100
• Stern MPU-200

Related tips

• New replacement MPU boards exist
• MPU LED never lights at all
• LED lamps flicker and displays shimmer with a replacement MPU: adjust its trim pot
• Dark MPU LED: follow +12 V through R29 and Q2
• MPU stops before the 7th LED flash (no 43 V)
• Intermittent or dead MPU from old closed-frame sockets
• Testing an MPU in the game with only J4 connected
• MPU board test points

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part One, Clay Harrell (pinrepair.com)